Chapter 060. Enlargement of Lymph Nodes and Spleen (Part 8)

The absence of the spleen has minimal long-term effects on the hematologic profile. In the immediate postsplenectomy period, leukocytosis (up to 25,000/µL) and thrombocytosis (up to 1 x 106/µL) may develop, but within 2–3 weeks, blood cell counts and survival of each cell lineage are usually normal. The chronic manifestations of splenectomy are marked variation in size and shape of erythrocytes (anisocytosis, poikilocytosis) and the presence of Howell-Jolly bodies (nuclear remnants), Heinz bodies (denatured hemoglobin), basophilic stippling, and an occasional nucleated erythrocyte in the peripheral blood. When such erythrocyte abnormalities appear in a patient whose spleen has not been...
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Chapter 060. Enlargement of Lymph Nodes and Spleen (Part 8) Chapter 060. Enlargement of Lymph Nodes and Spleen (Part 8) The absence of the spleen has minimal long-term effects on thehematologic profile. In the immediate postsplenectomy period, leukocytosis (up to25,000/µL) and thrombocytosis (up to 1 x 106/µL) may develop, but within 2–3weeks, blood cell counts and survival of each cell lineage are usually normal. Thechronic manifestations of splenectomy are marked variation in size and shape oferythrocytes (anisocytosis, poikilocytosis) and the presence of Howell-Jolly bodies(nuclear remnants), Heinz bodies (denatured hemoglobin), basophilic stippling,and an occasional nucleated erythrocyte in the peripheral blood. When sucherythrocyte abnormalities appear in a patient whose spleen has not been removed,one should suspect splenic infiltration by tumor that has interfered with its normalculling and pitting function. The most serious consequence of splenectomy is increased susceptibility tobacterial infections, particularly those with capsules such as Streptococcuspneumoniae, Haemophilus influenzae, and some gram-negative enteric organisms.Patients under age 20 years are particularly susceptible to overwhelming sepsiswith S. pneumoniae, and the overall actuarial risk of sepsis in patients who havehad their spleens removed is about 7% in 10 years. The case-fatality rate forpneumococcal sepsis in splenectomized patients is 50–80%. About 25% ofpatients without spleens will develop a serious infection at some time in their life.The frequency is highest within the first 3 years after splenectomy. About 15% ofthe infections are polymicrobial, and lung, skin, and blood are the most commonsites. No increased risk of viral infection has been noted in patients who have nospleen. The susceptibility to bacterial infections relates to the inability to removeopsonized bacteria from the bloodstream and a defect in making antibodies to Tcell–independent antigens such as the polysaccharide components of bacterialcapsules. Pneumococcal vaccine (23-valent polysaccharide vaccine) should beadministered to all patients 2 weeks before elective splenectomy. The AdvisoryCommittee on Immunization Practices recommends that even splenectomizedpatients receive pneumococcal vaccine with a repeat vaccination 5 years later.Efficacy has not been proven in this setting, and the recommendation discounts thepossibility that administration of the vaccine may actually lower the titer ofspecific pneumococcal antibodies. A more effective pneumococcal conjugatevaccine that involves T cells in the response is now available (Prevenar, 7-valent).The vaccine to Neisseria meningitidis should also be given to patients in whomelective splenectomy is planned. Although efficacy data for Haemophilusinfluenzae type b vaccine are not available for older children or adults, it may begiven to patients who have had a splenectomy. Splenectomized patients should be educated to consider any unexplainedfever as a medical emergency. Prompt medical attention with evaluation andtreatment of suspected bacteremia may be life-saving. Routine chemoprophylaxiswith oral penicillin can result in the emergence of drug-resistant strains and is notrecommended. In addition to an increased susceptibility to bacterial infections,splenectomized patients are also more susceptible to the parasitic diseasebabesiosis. The splenectomized patient should avoid areas where the parasiteBabesia is endemic (e.g., Cape Cod, MA). Surgical removal of the spleen is an obvious cause of hyposplenism.Patients with sickle cell disease often suffer from autosplenectomy as a result ofsplenic destruction by the numerous infarcts associated with sickle cell crisesduring childhood. Indeed, the presence of a palpable spleen in a patient with sicklecell disease after age 5 suggests a coexisting hemoglobinopathy, e.g., thalassemiaor hemoglobin C. In addition, patients who receive splenic irradiation for aneoplastic or autoimmune disease are also functionally hyposplenic. The termhyposplenism is preferred to asplenism in referring to the physiologicconsequences of splenectomy because asplenia is a rare, specific, and fatalcongenital abnormality in which there is a failure of the left side of the coelomiccavity (which includes the splenic anlagen) to develop normally. Infants withasplenia have no spleens, but that is the least of their problems. The right side ofthe developing embryo is duplicated on the left so there is liver where the spleenshould be, there are two right lungs, and the heart comprises two right atria andtwo right ventricles. Further Readings Barkun AN et al: The bedside assessment of splenic enlargement. Am JMed 91:512, 1991 [PMID: 1951414] Graves SA et al: Does this patient have splenomegaly? JAMA 270:2218,1993 Kraus MD et al: The spleen as a diagnostic specimen: A review of tenyears experience at two tertiary care institutions. Cancer 91:2001, 2001 [PMID:11391578] McIntyre OR, Ebaugh FG Jr: Palpable spleens: Ten year follow-up. AnnIntern Med 90:130, 1979 [PMID: 420452] Pangalis GA et al: Clinical approach to lymphadenopathy. Semin Oncol20:570, 1993 [PMID: 8296196] Recommended Adult Immunization Schedule—United States, October2005–September 2006. MMWR 54(40):Q1, 2005 Williamson HA Jr: Lymphadenopathy in a family practice: A descriptivestudy of 240 cases. J Fam Pract 20:449, 1985 [PMID: 3989485] . Bibliography Barkun AN et al: Splenic enlargement and Traubes space: How useful ispercussion? Am J Med 87:562, 1989 [PMID: 2683766] Castell DO: The spleen percussion sign: A useful diagnostic ...